gio/gresolver.c

   1 /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
   2
   3 /* GIO - GLib Input, Output and Streaming Library
   4  *
   5  * Copyright (C) 2008 Red Hat, Inc.
   6  *
   7  * This library is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2 of the License, or (at your option) any later version.
  11  *
  12  * This library is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General
  18  * Public License along with this library; if not, write to the
  19  * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  20  * Boston, MA 02111-1307, USA.
  21  */
  22
  23 #include "config.h"
  24 #include <glib.h>
  25 #include "glibintl.h"
  26
  27 #include "gresolver.h"
  28 #include "gnetworkingprivate.h"
  29 #include "gasyncresult.h"
  30 #include "ginetaddress.h"
  31 #include "ginetsocketaddress.h"
  32 #include "gsimpleasyncresult.h"
  33 #include "gsrvtarget.h"
  34
  35 #ifdef G_OS_UNIX
  36 #include "gunixresolver.h"
  37 #include <sys/stat.h>
  38 #endif
  39 #ifdef G_OS_WIN32
  40 #include "gwin32resolver.h"
  41 #endif
  42
  43 #include <stdlib.h>
  44
  45
  46 /**
  47  * SECTION:gresolver
  48  * @short_description: Asynchronous and cancellable DNS resolver
  49  * @include: gio/gio.h
  50  *
  51  * #GResolver provides cancellable synchronous and asynchronous DNS
  52  * resolution, for hostnames (g_resolver_lookup_by_address(),
  53  * g_resolver_lookup_by_name() and their async variants) and SRV
  54  * (service) records (g_resolver_lookup_service()).
  55  *
  56  * #GNetworkAddress and #GNetworkService provide wrappers around
  57  * #GResolver functionality that also implement #GSocketConnectable,
  58  * making it easy to connect to a remote host/service.
  59  */
  60
  61 enum {
  62   RELOAD,
  63   LAST_SIGNAL
  64 };
  65
  66 static guint signals[LAST_SIGNAL] = { 0 };
  67
  68 struct _GResolverPrivate {
  69 #ifdef G_OS_UNIX
  70   time_t resolv_conf_timestamp;
  71 #else
  72   int dummy;
  73 #endif
  74 };
  75
  76 /**
  77  * GResolver:
  78  *
  79  * The object that handles DNS resolution. Use g_resolver_get_default()
  80  * to get the default resolver.
  81  */
  82 G_DEFINE_TYPE (GResolver, g_resolver, G_TYPE_OBJECT)
  83
  84 static void
  85 g_resolver_class_init (GResolverClass *resolver_class)
  86 {
  87   volatile GType type;
  88
  89   g_type_class_add_private (resolver_class, sizeof (GResolverPrivate));
  90
  91   /* Make sure _g_networking_init() has been called */
  92   type = g_inet_address_get_type ();
  93   (type); /* To avoid -Wunused-but-set-variable */
  94
  95   /* Initialize _g_resolver_addrinfo_hints */
  96 #ifdef AI_ADDRCONFIG
  97   _g_resolver_addrinfo_hints.ai_flags |= AI_ADDRCONFIG;
  98 #endif
  99   /* These two don't actually matter, they just get copied into the
 100    * returned addrinfo structures (and then we ignore them). But if
 101    * we leave them unset, we'll get back duplicate answers.
 102    */
 103   _g_resolver_addrinfo_hints.ai_socktype = SOCK_STREAM;
 104   _g_resolver_addrinfo_hints.ai_protocol = IPPROTO_TCP;
 105
 106   /**
 107    * GResolver::reload:
 108    * @resolver: a #GResolver
 109    *
 110    * Emitted when the resolver notices that the system resolver
 111    * configuration has changed.
 112    **/
 113   signals[RELOAD] =
 114     g_signal_new (I_("reload"),
 115                   G_TYPE_RESOLVER,
 116                   G_SIGNAL_RUN_LAST,
 117                   G_STRUCT_OFFSET (GResolverClass, reload),
 118                   NULL, NULL,
 119                   g_cclosure_marshal_VOID__VOID,
 120                   G_TYPE_NONE, 0);
 121 }
 122
 123 static void
 124 g_resolver_init (GResolver *resolver)
 125 {
 126 #ifdef G_OS_UNIX
 127   struct stat st;
 128 #endif
 129
 130   resolver->priv = G_TYPE_INSTANCE_GET_PRIVATE (resolver, G_TYPE_RESOLVER, GResolverPrivate);
 131
 132 #ifdef G_OS_UNIX
 133   if (stat (_PATH_RESCONF, &st) == 0)
 134     resolver->priv->resolv_conf_timestamp = st.st_mtime;
 135 #endif
 136 }
 137
 138 static GResolver *default_resolver;
 139
 140 /**
 141  * g_resolver_get_default:
 142  *
 143  * Gets the default #GResolver. You should unref it when you are done
 144  * with it. #GResolver may use its reference count as a hint about how
 145  * many threads/processes, etc it should allocate for concurrent DNS
 146  * resolutions.
 147  *
 148  * Return value: (transfer full): the default #GResolver.
 149  *
 150  * Since: 2.22
 151  */
 152 GResolver *
 153 g_resolver_get_default (void)
 154 {
 155   if (!default_resolver)
 156     {
 157       if (g_thread_supported ())
 158         default_resolver = g_object_new (G_TYPE_THREADED_RESOLVER, NULL);
 159       else
 160         {
 161 #if defined(G_OS_UNIX)
 162           default_resolver = g_object_new (G_TYPE_UNIX_RESOLVER, NULL);
 163 #elif defined(G_OS_WIN32)
 164           default_resolver = g_object_new (G_TYPE_WIN32_RESOLVER, NULL);
 165 #endif
 166         }
 167     }
 168
 169   return g_object_ref (default_resolver);
 170 }
 171
 172 /**
 173  * g_resolver_set_default:
 174  * @resolver: the new default #GResolver
 175  *
 176  * Sets @resolver to be the application's default resolver (reffing
 177  * @resolver, and unreffing the previous default resolver, if any).
 178  * Future calls to g_resolver_get_default() will return this resolver.
 179  *
 180  * This can be used if an application wants to perform any sort of DNS
 181  * caching or "pinning"; it can implement its own #GResolver that
 182  * calls the original default resolver for DNS operations, and
 183  * implements its own cache policies on top of that, and then set
 184  * itself as the default resolver for all later code to use.
 185  *
 186  * Since: 2.22
 187  */
 188 void
 189 g_resolver_set_default (GResolver *resolver)
 190 {
 191   if (default_resolver)
 192     g_object_unref (default_resolver);
 193   default_resolver = g_object_ref (resolver);
 194 }
 195
 196
 197 static void
 198 g_resolver_maybe_reload (GResolver *resolver)
 199 {
 200 #ifdef G_OS_UNIX
 201   struct stat st;
 202
 203   if (stat (_PATH_RESCONF, &st) == 0)
 204     {
 205       if (st.st_mtime != resolver->priv->resolv_conf_timestamp)
 206         {
 207           resolver->priv->resolv_conf_timestamp = st.st_mtime;
 208           res_init ();
 209           g_signal_emit (resolver, signals[RELOAD], 0);
 210         }
 211     }
 212 #endif
 213 }
 214
 215 /* filter out duplicates, cf. https://bugzilla.gnome.org/show_bug.cgi?id=631379 */
 216 static void
 217 remove_duplicates (GList *addrs)
 218 {
 219   GList *l;
 220   GList *ll;
 221   GList *lll;
 222
 223   /* TODO: if this is too slow (it's O(n^2) but n is typically really
 224    * small), we can do something more clever but note that we must not
 225    * change the order of elements...
 226    */
 227   for (l = addrs; l != NULL; l = l->next)
 228     {
 229       GInetAddress *address = G_INET_ADDRESS (l->data);
 230       for (ll = l->next; ll != NULL; ll = lll)
 231         {
 232           GInetAddress *other_address = G_INET_ADDRESS (ll->data);
 233           lll = ll->next;
 234           if (g_inet_address_equal (address, other_address))
 235             {
 236               g_object_unref (other_address);
 237               /* we never return the first element */
 238               g_warn_if_fail (g_list_delete_link (addrs, ll) == addrs);
 239             }
 240         }
 241     }
 242 }
 243
 244
 245 /**
 246  * g_resolver_lookup_by_name:
 247  * @resolver: a #GResolver
 248  * @hostname: the hostname to look up
 249  * @cancellable: (allow-none): a #GCancellable, or %NULL
 250  * @error: return location for a #GError, or %NULL
 251  *
 252  * Synchronously resolves @hostname to determine its associated IP
 253  * address(es). @hostname may be an ASCII-only or UTF-8 hostname, or
 254  * the textual form of an IP address (in which case this just becomes
 255  * a wrapper around g_inet_address_new_from_string()).
 256  *
 257  * On success, g_resolver_lookup_by_name() will return a #GList of
 258  * #GInetAddress, sorted in order of preference and guaranteed to not
 259  * contain duplicates. That is, if using the result to connect to
 260  * @hostname, you should attempt to connect to the first address
 261  * first, then the second if the first fails, etc. If you are using
 262  * the result to listen on a socket, it is appropriate to add each
 263  * result using e.g. g_socket_listener_add_address().
 264  *
 265  * If the DNS resolution fails, @error (if non-%NULL) will be set to a
 266  * value from #GResolverError.
 267  *
 268  * If @cancellable is non-%NULL, it can be used to cancel the
 269  * operation, in which case @error (if non-%NULL) will be set to
 270  * %G_IO_ERROR_CANCELLED.
 271  *
 272  * If you are planning to connect to a socket on the resolved IP
 273  * address, it may be easier to create a #GNetworkAddress and use its
 274  * #GSocketConnectable interface.
 275  *
 276  * Return value: (element-type GInetAddress) (transfer full): a #GList
 277  * of #GInetAddress, or %NULL on error. You
 278  * must unref each of the addresses and free the list when you are
 279  * done with it. (You can use g_resolver_free_addresses() to do this.)
 280  *
 281  * Since: 2.22
 282  */
 283 GList *
 284 g_resolver_lookup_by_name (GResolver     *resolver,
 285                            const gchar   *hostname,
 286                            GCancellable  *cancellable,
 287                            GError       **error)
 288 {
 289   GInetAddress *addr;
 290   GList *addrs;
 291   gchar *ascii_hostname = NULL;
 292
 293   g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
 294   g_return_val_if_fail (hostname != NULL, NULL);
 295
 296   /* Check if @hostname is just an IP address */
 297   addr = g_inet_address_new_from_string (hostname);
 298   if (addr)
 299     return g_list_append (NULL, addr);
 300
 301   if (g_hostname_is_non_ascii (hostname))
 302     hostname = ascii_hostname = g_hostname_to_ascii (hostname);
 303
 304   g_resolver_maybe_reload (resolver);
 305   addrs = G_RESOLVER_GET_CLASS (resolver)->
 306     lookup_by_name (resolver, hostname, cancellable, error);
 307
 308   remove_duplicates (addrs);
 309
 310   g_free (ascii_hostname);
 311   return addrs;
 312 }
 313
 314 /**
 315  * g_resolver_lookup_by_name_async:
 316  * @resolver: a #GResolver
 317  * @hostname: the hostname to look up the address of
 318  * @cancellable: (allow-none): a #GCancellable, or %NULL
 319  * @callback: (scope async): callback to call after resolution completes
 320  * @user_data: (closure): data for @callback
 321  *
 322  * Begins asynchronously resolving @hostname to determine its
 323  * associated IP address(es), and eventually calls @callback, which
 324  * must call g_resolver_lookup_by_name_finish() to get the result.
 325  * See g_resolver_lookup_by_name() for more details.
 326  *
 327  * Since: 2.22
 328  */
 329 void
 330 g_resolver_lookup_by_name_async (GResolver           *resolver,
 331                                  const gchar         *hostname,
 332                                  GCancellable        *cancellable,
 333                                  GAsyncReadyCallback  callback,
 334                                  gpointer             user_data)
 335 {
 336   GInetAddress *addr;
 337   gchar *ascii_hostname = NULL;
 338
 339   g_return_if_fail (G_IS_RESOLVER (resolver));
 340   g_return_if_fail (hostname != NULL);
 341
 342   /* Check if @hostname is just an IP address */
 343   addr = g_inet_address_new_from_string (hostname);
 344   if (addr)
 345     {
 346       GSimpleAsyncResult *simple;
 347
 348       simple = g_simple_async_result_new (G_OBJECT (resolver),
 349                                           callback, user_data,
 350                                           g_resolver_lookup_by_name_async);
 351
 352       g_simple_async_result_set_op_res_gpointer (simple, addr, g_object_unref);
 353       g_simple_async_result_complete_in_idle (simple);
 354       g_object_unref (simple);
 355       return;
 356     }
 357
 358   if (g_hostname_is_non_ascii (hostname))
 359     hostname = ascii_hostname = g_hostname_to_ascii (hostname);
 360
 361   g_resolver_maybe_reload (resolver);
 362   G_RESOLVER_GET_CLASS (resolver)->
 363     lookup_by_name_async (resolver, hostname, cancellable, callback, user_data);
 364
 365   g_free (ascii_hostname);
 366 }
 367
 368 /**
 369  * g_resolver_lookup_by_name_finish:
 370  * @resolver: a #GResolver
 371  * @result: the result passed to your #GAsyncReadyCallback
 372  * @error: return location for a #GError, or %NULL
 373  *
 374  * Retrieves the result of a call to
 375  * g_resolver_lookup_by_name_async().
 376  *
 377  * If the DNS resolution failed, @error (if non-%NULL) will be set to
 378  * a value from #GResolverError. If the operation was cancelled,
 379  * @error will be set to %G_IO_ERROR_CANCELLED.
 380  *
 381  * Return value: (element-type GInetAddress) (transfer full): a #GList
 382  * of #GInetAddress, or %NULL on error. See g_resolver_lookup_by_name()
 383  * for more details.
 384  *
 385  * Since: 2.22
 386  */
 387 GList *
 388 g_resolver_lookup_by_name_finish (GResolver     *resolver,
 389                                   GAsyncResult  *result,
 390                                   GError       **error)
 391 {
 392   GList *addrs;
 393
 394   g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
 395
 396   if (G_IS_SIMPLE_ASYNC_RESULT (result))
 397     {
 398       GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (result);
 399
 400       if (g_simple_async_result_propagate_error (simple, error))
 401         return NULL;
 402
 403       /* Handle the stringified-IP-addr case */
 404       if (g_simple_async_result_get_source_tag (simple) == g_resolver_lookup_by_name_async)
 405         {
 406           GInetAddress *addr;
 407
 408           addr = g_simple_async_result_get_op_res_gpointer (simple);
 409           return g_list_append (NULL, g_object_ref (addr));
 410         }
 411     }
 412
 413   addrs = G_RESOLVER_GET_CLASS (resolver)->
 414     lookup_by_name_finish (resolver, result, error);
 415
 416   remove_duplicates (addrs);
 417
 418   return addrs;
 419 }
 420
 421 /**
 422  * g_resolver_free_addresses: (skip)
 423  * @addresses: a #GList of #GInetAddress
 424  *
 425  * Frees @addresses (which should be the return value from
 426  * g_resolver_lookup_by_name() or g_resolver_lookup_by_name_finish()).
 427  * (This is a convenience method; you can also simply free the results
 428  * by hand.)
 429  *
 430  * Since: 2.22
 431  */
 432 void
 433 g_resolver_free_addresses (GList *addresses)
 434 {
 435   GList *a;
 436
 437   for (a = addresses; a; a = a->next)
 438     g_object_unref (a->data);
 439   g_list_free (addresses);
 440 }
 441
 442 /**
 443  * g_resolver_lookup_by_address:
 444  * @resolver: a #GResolver
 445  * @address: the address to reverse-resolve
 446  * @cancellable: (allow-none): a #GCancellable, or %NULL
 447  * @error: return location for a #GError, or %NULL
 448  *
 449  * Synchronously reverse-resolves @address to determine its
 450  * associated hostname.
 451  *
 452  * If the DNS resolution fails, @error (if non-%NULL) will be set to
 453  * a value from #GResolverError.
 454  *
 455  * If @cancellable is non-%NULL, it can be used to cancel the
 456  * operation, in which case @error (if non-%NULL) will be set to
 457  * %G_IO_ERROR_CANCELLED.
 458  *
 459  * Return value: a hostname (either ASCII-only, or in ASCII-encoded
 460  *     form), or %NULL on error.
 461  *
 462  * Since: 2.22
 463  */
 464 gchar *
 465 g_resolver_lookup_by_address (GResolver     *resolver,
 466                               GInetAddress  *address,
 467                               GCancellable  *cancellable,
 468                               GError       **error)
 469 {
 470   g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
 471   g_return_val_if_fail (G_IS_INET_ADDRESS (address), NULL);
 472
 473   g_resolver_maybe_reload (resolver);
 474   return G_RESOLVER_GET_CLASS (resolver)->
 475     lookup_by_address (resolver, address, cancellable, error);
 476 }
 477
 478 /**
 479  * g_resolver_lookup_by_address_async:
 480  * @resolver: a #GResolver
 481  * @address: the address to reverse-resolve
 482  * @cancellable: (allow-none): a #GCancellable, or %NULL
 483  * @callback: (scope async): callback to call after resolution completes
 484  * @user_data: (closure): data for @callback
 485  *
 486  * Begins asynchronously reverse-resolving @address to determine its
 487  * associated hostname, and eventually calls @callback, which must
 488  * call g_resolver_lookup_by_address_finish() to get the final result.
 489  *
 490  * Since: 2.22
 491  */
 492 void
 493 g_resolver_lookup_by_address_async (GResolver           *resolver,
 494                                     GInetAddress        *address,
 495                                     GCancellable        *cancellable,
 496                                     GAsyncReadyCallback  callback,
 497                                     gpointer             user_data)
 498 {
 499   g_return_if_fail (G_IS_RESOLVER (resolver));
 500   g_return_if_fail (G_IS_INET_ADDRESS (address));
 501
 502   g_resolver_maybe_reload (resolver);
 503   G_RESOLVER_GET_CLASS (resolver)->
 504     lookup_by_address_async (resolver, address, cancellable, callback, user_data);
 505 }
 506
 507 /**
 508  * g_resolver_lookup_by_address_finish:
 509  * @resolver: a #GResolver
 510  * @result: the result passed to your #GAsyncReadyCallback
 511  * @error: return location for a #GError, or %NULL
 512  *
 513  * Retrieves the result of a previous call to
 514  * g_resolver_lookup_by_address_async().
 515  *
 516  * If the DNS resolution failed, @error (if non-%NULL) will be set to
 517  * a value from #GResolverError. If the operation was cancelled,
 518  * @error will be set to %G_IO_ERROR_CANCELLED.
 519  *
 520  * Return value: a hostname (either ASCII-only, or in ASCII-encoded
 521  * form), or %NULL on error.
 522  *
 523  * Since: 2.22
 524  */
 525 gchar *
 526 g_resolver_lookup_by_address_finish (GResolver     *resolver,
 527                                      GAsyncResult  *result,
 528                                      GError       **error)
 529 {
 530   g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
 531
 532   if (G_IS_SIMPLE_ASYNC_RESULT (result))
 533     {
 534       GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (result);
 535
 536       if (g_simple_async_result_propagate_error (simple, error))
 537         return NULL;
 538     }
 539
 540   return G_RESOLVER_GET_CLASS (resolver)->
 541     lookup_by_address_finish (resolver, result, error);
 542 }
 543
 544 static gchar *
 545 g_resolver_get_service_rrname (const char *service,
 546                                const char *protocol,
 547                                const char *domain)
 548 {
 549   gchar *rrname, *ascii_domain = NULL;
 550
 551   if (g_hostname_is_non_ascii (domain))
 552     domain = ascii_domain = g_hostname_to_ascii (domain);
 553
 554   rrname = g_strdup_printf ("_%s._%s.%s", service, protocol, domain);
 555
 556   g_free (ascii_domain);
 557   return rrname;
 558 }
 559
 560 /**
 561  * g_resolver_lookup_service:
 562  * @resolver: a #GResolver
 563  * @service: the service type to look up (eg, "ldap")
 564  * @protocol: the networking protocol to use for @service (eg, "tcp")
 565  * @domain: the DNS domain to look up the service in
 566  * @cancellable: (allow-none): a #GCancellable, or %NULL
 567  * @error: return location for a #GError, or %NULL
 568  *
 569  * Synchronously performs a DNS SRV lookup for the given @service and
 570  * @protocol in the given @domain and returns an array of #GSrvTarget.
 571  * @domain may be an ASCII-only or UTF-8 hostname. Note also that the
 572  * @service and @protocol arguments <emphasis>do not</emphasis>
 573  * include the leading underscore that appears in the actual DNS
 574  * entry.
 575  *
 576  * On success, g_resolver_lookup_service() will return a #GList of
 577  * #GSrvTarget, sorted in order of preference. (That is, you should
 578  * attempt to connect to the first target first, then the second if
 579  * the first fails, etc.)
 580  *
 581  * If the DNS resolution fails, @error (if non-%NULL) will be set to
 582  * a value from #GResolverError.
 583  *
 584  * If @cancellable is non-%NULL, it can be used to cancel the
 585  * operation, in which case @error (if non-%NULL) will be set to
 586  * %G_IO_ERROR_CANCELLED.
 587  *
 588  * If you are planning to connect to the service, it is usually easier
 589  * to create a #GNetworkService and use its #GSocketConnectable
 590  * interface.
 591  *
 592  * Return value: (element-type GSrvTarget) (transfer full): a #GList of #GSrvTarget,
 593  * or %NULL on error. You must free each of the targets and the list when you are
 594  * done with it. (You can use g_resolver_free_targets() to do this.)
 595  *
 596  * Since: 2.22
 597  */
 598 GList *
 599 g_resolver_lookup_service (GResolver     *resolver,
 600                            const gchar   *service,
 601                            const gchar   *protocol,
 602                            const gchar   *domain,
 603                            GCancellable  *cancellable,
 604                            GError       **error)
 605 {
 606   GList *targets;
 607   gchar *rrname;
 608
 609   g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
 610   g_return_val_if_fail (service != NULL, NULL);
 611   g_return_val_if_fail (protocol != NULL, NULL);
 612   g_return_val_if_fail (domain != NULL, NULL);
 613
 614   rrname = g_resolver_get_service_rrname (service, protocol, domain);
 615
 616   g_resolver_maybe_reload (resolver);
 617   targets = G_RESOLVER_GET_CLASS (resolver)->
 618     lookup_service (resolver, rrname, cancellable, error);
 619
 620   g_free (rrname);
 621   return targets;
 622 }
 623
 624 /**
 625  * g_resolver_lookup_service_async:
 626  * @resolver: a #GResolver
 627  * @service: the service type to look up (eg, "ldap")
 628  * @protocol: the networking protocol to use for @service (eg, "tcp")
 629  * @domain: the DNS domain to look up the service in
 630  * @cancellable: (allow-none): a #GCancellable, or %NULL
 631  * @callback: (scope async): callback to call after resolution completes
 632  * @user_data: (closure): data for @callback
 633  *
 634  * Begins asynchronously performing a DNS SRV lookup for the given
 635  * @service and @protocol in the given @domain, and eventually calls
 636  * @callback, which must call g_resolver_lookup_service_finish() to
 637  * get the final result. See g_resolver_lookup_service() for more
 638  * details.
 639  *
 640  * Since: 2.22
 641  */
 642 void
 643 g_resolver_lookup_service_async (GResolver           *resolver,
 644                                  const gchar         *service,
 645                                  const gchar         *protocol,
 646                                  const gchar         *domain,
 647                                  GCancellable        *cancellable,
 648                                  GAsyncReadyCallback  callback,
 649                                  gpointer             user_data)
 650 {
 651   gchar *rrname;
 652
 653   g_return_if_fail (G_IS_RESOLVER (resolver));
 654   g_return_if_fail (service != NULL);
 655   g_return_if_fail (protocol != NULL);
 656   g_return_if_fail (domain != NULL);
 657
 658   rrname = g_resolver_get_service_rrname (service, protocol, domain);
 659
 660   g_resolver_maybe_reload (resolver);
 661   G_RESOLVER_GET_CLASS (resolver)->
 662     lookup_service_async (resolver, rrname, cancellable, callback, user_data);
 663
 664   g_free (rrname);
 665 }
 666
 667 /**
 668  * g_resolver_lookup_service_finish:
 669  * @resolver: a #GResolver
 670  * @result: the result passed to your #GAsyncReadyCallback
 671  * @error: return location for a #GError, or %NULL
 672  *
 673  * Retrieves the result of a previous call to
 674  * g_resolver_lookup_service_async().
 675  *
 676  * If the DNS resolution failed, @error (if non-%NULL) will be set to
 677  * a value from #GResolverError. If the operation was cancelled,
 678  * @error will be set to %G_IO_ERROR_CANCELLED.
 679  *
 680  * Return value: (element-type GSrvTarget) (transfer full): a #GList of #GSrvTarget,
 681  * or %NULL on error. See g_resolver_lookup_service() for more details.
 682  *
 683  * Since: 2.22
 684  */
 685 GList *
 686 g_resolver_lookup_service_finish (GResolver     *resolver,
 687                                   GAsyncResult  *result,
 688                                   GError       **error)
 689 {
 690   g_return_val_if_fail (G_IS_RESOLVER (resolver), NULL);
 691
 692   if (G_IS_SIMPLE_ASYNC_RESULT (result))
 693     {
 694       GSimpleAsyncResult *simple = G_SIMPLE_ASYNC_RESULT (result);
 695
 696       if (g_simple_async_result_propagate_error (simple, error))
 697         return NULL;
 698     }
 699
 700   return G_RESOLVER_GET_CLASS (resolver)->
 701     lookup_service_finish (resolver, result, error);
 702 }
 703
 704 /**
 705  * g_resolver_free_targets: (skip)
 706  * @targets: a #GList of #GSrvTarget
 707  *
 708  * Frees @targets (which should be the return value from
 709  * g_resolver_lookup_service() or g_resolver_lookup_service_finish()).
 710  * (This is a convenience method; you can also simply free the
 711  * results by hand.)
 712  *
 713  * Since: 2.22
 714  */
 715 void
 716 g_resolver_free_targets (GList *targets)
 717 {
 718   GList *t;
 719
 720   for (t = targets; t; t = t->next)
 721     g_srv_target_free (t->data);
 722   g_list_free (targets);
 723 }
 724
 725 /**
 726  * g_resolver_error_quark:
 727  *
 728  * Gets the #GResolver Error Quark.
 729  *
 730  * Return value: a #GQuark.
 731  *
 732  * Since: 2.22
 733  */
 734 GQuark
 735 g_resolver_error_quark (void)
 736 {
 737   return g_quark_from_static_string ("g-resolver-error-quark");
 738 }
 739
 740
 741 static GResolverError
 742 g_resolver_error_from_addrinfo_error (gint err)
 743 {
 744   switch (err)
 745     {
 746     case EAI_FAIL:
 747 #if defined(EAI_NODATA) && (EAI_NODATA != EAI_NONAME)
 748     case EAI_NODATA:
 749 #endif
 750     case EAI_NONAME:
 751       return G_RESOLVER_ERROR_NOT_FOUND;
 752
 753     case EAI_AGAIN:
 754       return G_RESOLVER_ERROR_TEMPORARY_FAILURE;
 755
 756     default:
 757       return G_RESOLVER_ERROR_INTERNAL;
 758     }
 759 }
 760
 761 struct addrinfo _g_resolver_addrinfo_hints;
 762
 763 /* Private method to process a getaddrinfo() response. */
 764 GList *
 765 _g_resolver_addresses_from_addrinfo (const char       *hostname,
 766                                      struct addrinfo  *res,
 767                                      gint              gai_retval,
 768                                      GError          **error)
 769 {
 770   struct addrinfo *ai;
 771   GSocketAddress *sockaddr;
 772   GInetAddress *addr;
 773   GList *addrs;
 774
 775   if (gai_retval != 0)
 776     {
 777       g_set_error (error, G_RESOLVER_ERROR,
 778                    g_resolver_error_from_addrinfo_error (gai_retval),
 779                    _("Error resolving '%s': %s"),
 780                    hostname, gai_strerror (gai_retval));
 781       return NULL;
 782     }
 783
 784   g_return_val_if_fail (res != NULL, NULL);
 785
 786   addrs = NULL;
 787   for (ai = res; ai; ai = ai->ai_next)
 788     {
 789       sockaddr = g_socket_address_new_from_native (ai->ai_addr, ai->ai_addrlen);
 790       if (!sockaddr || !G_IS_INET_SOCKET_ADDRESS (sockaddr))
 791         continue;
 792
 793       addr = g_object_ref (g_inet_socket_address_get_address ((GInetSocketAddress *)sockaddr));
 794       addrs = g_list_prepend (addrs, addr);
 795       g_object_unref (sockaddr);
 796     }
 797
 798   return g_list_reverse (addrs);
 799 }
 800
 801 /* Private method to set up a getnameinfo() request */
 802 void
 803 _g_resolver_address_to_sockaddr (GInetAddress            *address,
 804                                  struct sockaddr_storage *sa,
 805                                  gsize                   *len)
 806 {
 807   GSocketAddress *sockaddr;
 808
 809   sockaddr = g_inet_socket_address_new (address, 0);
 810   g_socket_address_to_native (sockaddr, (struct sockaddr *)sa, sizeof (*sa), NULL);
 811   *len = g_socket_address_get_native_size (sockaddr);
 812   g_object_unref (sockaddr);
 813 }
 814
 815 /* Private method to process a getnameinfo() response. */
 816 char *
 817 _g_resolver_name_from_nameinfo (GInetAddress  *address,
 818                                 const gchar   *name,
 819                                 gint           gni_retval,
 820                                 GError       **error)
 821 {
 822   if (gni_retval != 0)
 823     {
 824       gchar *phys;
 825
 826       phys = g_inet_address_to_string (address);
 827       g_set_error (error, G_RESOLVER_ERROR,
 828                    g_resolver_error_from_addrinfo_error (gni_retval),
 829                    _("Error reverse-resolving '%s': %s"),
 830                    phys ? phys : "(unknown)", gai_strerror (gni_retval));
 831       g_free (phys);
 832       return NULL;
 833     }
 834
 835   return g_strdup (name);
 836 }
 837
 838 #if defined(G_OS_UNIX)
 839 /* Private method to process a res_query response into GSrvTargets */
 840 GList *
 841 _g_resolver_targets_from_res_query (const gchar      *rrname,
 842                                     guchar           *answer,
 843                                     gint              len,
 844                                     gint              herr,
 845                                     GError          **error)
 846 {
 847   gint count;
 848   gchar namebuf[1024];
 849   guchar *end, *p;
 850   guint16 type, qclass, rdlength, priority, weight, port;
 851   guint32 ttl;
 852   HEADER *header;
 853   GSrvTarget *target;
 854   GList *targets;
 855
 856   if (len <= 0)
 857     {
 858       GResolverError errnum;
 859       const gchar *format;
 860
 861       if (len == 0 || herr == HOST_NOT_FOUND || herr == NO_DATA)
 862         {
 863           errnum = G_RESOLVER_ERROR_NOT_FOUND;
 864           format = _("No service record for '%s'");
 865         }
 866       else if (herr == TRY_AGAIN)
 867         {
 868           errnum = G_RESOLVER_ERROR_TEMPORARY_FAILURE;
 869           format = _("Temporarily unable to resolve '%s'");
 870         }
 871       else
 872         {
 873           errnum = G_RESOLVER_ERROR_INTERNAL;
 874           format = _("Error resolving '%s'");
 875         }
 876
 877       g_set_error (error, G_RESOLVER_ERROR, errnum, format, rrname);
 878       return NULL;
 879     }
 880
 881   targets = NULL;
 882
 883   header = (HEADER *)answer;
 884   p = answer + sizeof (HEADER);
 885   end = answer + len;
 886
 887   /* Skip query */
 888   count = ntohs (header->qdcount);
 889   while (count-- && p < end)
 890     {
 891       p += dn_expand (answer, end, p, namebuf, sizeof (namebuf));
 892       p += 4;
 893     }
 894
 895   /* Read answers */
 896   count = ntohs (header->ancount);
 897   while (count-- && p < end)
 898     {
 899       p += dn_expand (answer, end, p, namebuf, sizeof (namebuf));
 900       GETSHORT (type, p);
 901       GETSHORT (qclass, p);
 902       GETLONG  (ttl, p);
 903       ttl = ttl; /* To avoid -Wunused-but-set-variable */
 904       GETSHORT (rdlength, p);
 905
 906       if (type != T_SRV || qclass != C_IN)
 907         {
 908           p += rdlength;
 909           continue;
 910         }
 911
 912       GETSHORT (priority, p);
 913       GETSHORT (weight, p);
 914       GETSHORT (port, p);
 915       p += dn_expand (answer, end, p, namebuf, sizeof (namebuf));
 916
 917       target = g_srv_target_new (namebuf, port, priority, weight);
 918       targets = g_list_prepend (targets, target);
 919     }
 920
 921   return g_srv_target_list_sort (targets);
 922 }
 923 #elif defined(G_OS_WIN32)
 924 /* Private method to process a DnsQuery response into GSrvTargets */
 925 GList *
 926 _g_resolver_targets_from_DnsQuery (const gchar  *rrname,
 927                                    DNS_STATUS    status,
 928                                    DNS_RECORD   *results,
 929                                    GError      **error)
 930 {
 931   DNS_RECORD *rec;
 932   GSrvTarget *target;
 933   GList *targets;
 934
 935   if (status != ERROR_SUCCESS)
 936     {
 937       GResolverError errnum;
 938       const gchar *format;
 939
 940       if (status == DNS_ERROR_RCODE_NAME_ERROR)
 941         {
 942           errnum = G_RESOLVER_ERROR_NOT_FOUND;
 943           format = _("No service record for '%s'");
 944         }
 945       else if (status == DNS_ERROR_RCODE_SERVER_FAILURE)
 946         {
 947           errnum = G_RESOLVER_ERROR_TEMPORARY_FAILURE;
 948           format = _("Temporarily unable to resolve '%s'");
 949         }
 950       else
 951         {
 952           errnum = G_RESOLVER_ERROR_INTERNAL;
 953           format = _("Error resolving '%s'");
 954         }
 955
 956       g_set_error (error, G_RESOLVER_ERROR, errnum, format, rrname);
 957       return NULL;
 958     }
 959
 960   targets = NULL;
 961   for (rec = results; rec; rec = rec->pNext)
 962     {
 963       if (rec->wType != DNS_TYPE_SRV)
 964         continue;
 965
 966       target = g_srv_target_new (rec->Data.SRV.pNameTarget,
 967                                  rec->Data.SRV.wPort,
 968                                  rec->Data.SRV.wPriority,
 969                                  rec->Data.SRV.wWeight);
 970       targets = g_list_prepend (targets, target);
 971     }
 972
 973   return g_srv_target_list_sort (targets);
 974 }
 975
 976 #endif